The embodiments described herein generally relate to the technical field of CT imaging, in particular to a method for placing A/D converter, a front-lit Detector and a CT apparatus.
Detector is one of the most important components in a CT apparatus. The detector is used for converting X-rays emitted from a tube into electrical signals. Then an A/D converter converts the analog electrical signals into digital signals. Since the A/D converter is too large in size to be packaged in the detector, it is necessary to lead the analog electrical signals out of the detector, so that the A/D converter outside the detector converts the analog electrical signals into digital signals for further processing.
As we know, a detector will usually output hundreds and even thousands of analog electrical signals, so outputting the analog electrical signals out of the detector not only requires gigantic cables but also have critical requirements for signal integrity.
With the development of the ASIC (Application Specific Integrated Circuit) design technology, the size of the A/D converter has become small and the power thereof low enough to allow the A/D converter to be placed in the detector.
However, it is well-known that X-rays will damage the ASIC chips, thus how to place the A/D converter in the detector without being irradiated by the X-rays is the research hotspot at present.
U.S. Pat. No. 7,439,516, titled “Module assembly for multiple die back-illuminated diode” provides a solution of back-illuminated detector, which places the A/D converter between the diode and the substrate and is mainly used for high-end CT apparatus. Such a technical solution costs much and changes the structure of the back-illuminated detector a lot.